Porcelain enamel metal substrates are well-known in the prior art and are used extensively in electronic applications. Examples of such substrates and methods of making them are disclosed in U.S. Pat. Nos. 5,605,715 and 5,554,965.
In the prior art such metal coated substrates were generally produced by one of two methods. In one method, the coated substrates are produced individually or one at a time. Unfortunately, this can be a very time consuming and costly approach to producing the coated substrates. In another method, a chisel mark is placed in the base metal during metal fabrication to facilitate the separation of the substrate from the carrier gang frame. During the deposition of the porcelain coating on the base metal the chiseled area is also coated. During the breaking out of the substrate from the carrier gang frame a mechanical parting tool is required and the enamel coating produces fractures in the coating creating a friable unstable edge. Unfortunately, this edge is a source of contamination during subsequent processing and during the breaking out step the fracturing enamel can become an undesirable foreign body in the eyes of the worker who is conducting such breakout.